如何将数据从 recyclerview 适配器传递或发送到片段

Question

如何将数据从 recyclerview 适配器传递到片段以及我必须在片段中编写代码以接收数据。我已经检查了该网站中的链接，但遗憾的是无法获得正确的代码。 下面是代码

ExampleAdapter.Java

public class ExampleAdapter extends RecyclerView.Adapter<ExampleAdapter.ExampleViewHolder> {
    private ArrayList<ExampleItem> mExampleList;
    @NonNull
    @Override
    public ExampleViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        View v=LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.example_item,viewGroup,false);
        ExampleViewHolder evh=new ExampleViewHolder(v);
        return evh;
    }
    @Override
    public void onBindViewHolder(@NonNull ExampleViewHolder exampleViewHolder, int i) {
        final ExampleItem currentItem=mExampleList.get(i);
        exampleViewHolder.mTextView.setText(currentItem.getmText());
        exampleViewHolder.mTextView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // pass the data to the fragment
            }
        });
    }
    @Override
    public int getItemCount() {
        return mExampleList.size();
    }
    public static class ExampleViewHolder extends RecyclerView.ViewHolder {
        public TextView mTextView;
        public ExampleViewHolder(@NonNull View itemView) {
            super(itemView);
            mTextView=itemView.findViewById(R.id.texttitle);
        }
    }
    public ExampleAdapter(ArrayList<ExampleItem> exampleList){
              this.mExampleList=exampleList;
}
}

Answer 1

您可以通过将回调附加到适配器来传递数据：

创建界面：

interface OnTextClickListener {
    void onTextClick(ExampleItem data);
}

委托回调：

class ExampleAdapter extends RecyclerView.Adapter<ExampleAdapter.ExampleViewHolder> {

    List<ExampleItem> items;
    OnTextClickListener listener;

    ExampleAdapter(List<ExampleItem> items, OnTextClickListener listener) {
        this.items = items;
        this.listener = listener;
    }

    @Override
    public void onBindViewHolder(ExampleViewHolder viewHolder, int position) {
        viewHolder.textView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // Say you want to pass an ExampleItem back to the fragment...
                ExampleItem data = items.get(position);
                listener.onTextClick(data);
            }
        });
    }
}

用接口实现片段：

class YourFragment extends Fragment implements OnTextClickListener {

    public onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        recyclerView.setAdapter(new ExampleAdapter(this));
    }

    void onTextClick(ExampleItem data) {
        // Now you can do however you want with the data here...
        Toast.makeText(getActivity(), "Got: " + data, Toast.LENGTH_SHORT).show()
    }
}

Answer 2

你有两个选择；

使用SharedPreferences：

Context myContext = exampleViewHolder.itemView.getContext()

SharedPreferences.Editor editor = getSharedPreferences("DeviceToken", MODE_PRIVATE).edit();
editor.putString("YourKeyNameHere", currentItem.getmText()); // or add toString() after if needed
editor.apply();

_获取：

SharedPreferences prefs = getSharedPreferences("DeviceToken", MODE_PRIVATE);
String deviceToken = prefs.getString("YourKeyNameHere", null); // get it here

使用Intent：（如果你想在传递数据时启动另一个Activity）

Intent intent = new Intent(myContext , SignoutActivity.class);
intent.putExtra("EXTRA_TEXT", currentItem.getmText());
startActivity(intent); // if needed, add myContext before starting myContext.startActivity...

_获取：

String extraText = getIntent().getStringExtra("EXTRA_TEXT");

Answer 3

片段中有“ClickListener”。

例如。

@Override
public void onResume(){
    super.onResume();
    ((ExampleAdapter) mAdapter).onItemClick(new RecyclerViewItemClick() {
        @Override
        public void onItemClick(int position, View v) {
            //to do. ArrayList<> data.get(position).getYourItem();
        }
    });
}

而且你必须创建接口 RecyclerViewItemClick.java

public interface RecyclerViewItemClick {
    public void onItemClick(int position, View v);
}

最后。 ExampleAdapter.java 添加

public void onItemClick(RecyclerViewItemClick mclick){
   this.myClickListener = mclick;
}

ExampleViewHolder 方法添加

@Override
public void onClick(View v) {
    myClickListener.onItemClick(getAdapterPosition(), v);
    notifyDataSetChanged();
}

希望你能解决这个问题。谢谢。

Answer 4

有一个IDataCollector 接口。在Fragment 中实现她，将Fragment 引用作为构造函数参数传递，并在适配器内部使用它

public interface IDataCollector {
    void setText(String text);
    void setAnything(Object anything);
}

// Fragment

public class Fragment implements IDataCollector {

    private void initView() {
        // Add this as a parameter
        ExampleAdapter adapter = new ExampleAdapter(... , this);
    }

    @Override
    public void setText(String text){
        this.textField = text;
    }

    @Override
    public void setText(Object anything){
        this.anything = anything;
    }
}

// Adapter code

// Constructor, parameters ommited
public ExampleAdapter(...., IDataCollector dataCollector) {
    this.dataCollector = dataCollector;
}

@Override
public void onBindViewHolder(@NonNull ExampleViewHolder exampleViewHolder, int i) {
    final ExampleItem currentItem=mExampleList.get(i);
    exampleViewHolder.mTextView.setText(currentItem.getmText());
    exampleViewHolder.mTextView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            dataCollector.setText(((TextView)v.findViewById(R.id.label1)).getText());
            ....
        }
    });
}

Answer 5

通过接口你可以解决这个问题 1.在adapter中创建一个接口，添加需要的方法 2. 在需要的地方调用适配器中的这些方法 3.在fragment或activity中实现接口，将上下文传递给适配器